The most common disease associated with respiratory system is bronchitis. It is often accompanied by a cold or flu and affects people regardless of age. If your immune system is weak or you are a chain smoker, then you are greatly exposed to develop chronic bronchitis. In few cases, developing asthmatic bronchitis is also possible.

Smoking is considered to be a serious cause of bronchitis which can lead to other complications like pneumonia. The substances found in cigarettes as well other tobacco causes bronchial tubes irritation. Environmental pollution and exposures to chemicals can also lead to developing chronic bronchitis. In addition, second-hand smokes as shown in some studies can also cause chronic bronchitis.